Improvement in machines for cutting stone



ATENT FFICE.

DAVIS TILLSON, OF ROOKLAN D, MAINE.

IMPROVEMENT IN MACHINES FOR CUTTING STONE.

Specifioation forming part of Letters Patent No. 131,*797, dated October1, 1872.

To all 'whom 'it may 'camera: V

Be it known that I, DAVIS TILLSON, of

` Roekland, in the county of KnoX and State of Maine, have invented anImprovement in Stone-Outting Machines; and I do hereby declare that thefollowing, taken in connection with the drawin g which accompanies andform s part of this specification, is a description of ny inventionsufficient to enable those skilled in the art to practice it.

My invention relates to that class of stone-` dressing machines in whichengine-impelled drills are used, the invention having particularreference to lprovision for cushioning the drill-carriers in' theirreactionary movement. My invention consists, primarily, in making thedrill-carrier as a piston located in a reeiprocating-cylinder, thepiston being at the forward end of the cylinder, and its rebound afterthe blow being against the body of air between it and the cylinder-head.I use in connection with the drill-cylinder an air-compresso'r cylinder,by means of which the airis driven into and oompressed within thedrill-eylinder, so that the drill holder or piston reacts against thebody of compressed air.

The drawing represents asectional elevation of a drilling-engineembodying my invention.

a denotes the frame; b, a reciprocating drillcylinder, having at itsopposite sides slides c which slide on the guide-ways d of the frame a.At the front or lower end of the cylinder is a cylinder-head, e, throughwhich passes a shank or drill stock, f, which carries at its outer endthe drill.` This drill-shank or holder extends from a drill-head orpiston, g, in the eylinder b. At the opposte end of the cylinder b, andin aXial line with it, is another cylindex', IL, which is anair-compressor cylinder, and is attached to or forms a part of the oyl-`inder b, the slides e of the cylinder b being connected by pitmen z'with cranks Ic of a drivin gshaft, l, rotation of the "shaft" efi'ecting the reeiprocation of both cylinders. At the front end of the cylinderhis a head, m, which forms a partition between the two cylinders, and insaid cylinder h is a piston, n, which is, at the end of a rod, 0, fixedto and extending from the frame a, the rod-and pisten being stationary,and the eylinder h sliding upon the piston. At the inner side of thepiston n is a valve, p, which controls airinlets q passing through thepiston, and in the front of the head m is a similar valve, r,controlling openings s through said head, said opeings extending fromthe i compressor-cylinder chamber t into the drill-lead cylinder-chamberu.

The operation is as follows: When, by turning shaft l the eranks k arebrought to the opposite position to that shown in the drawing thecylinder h slides upon the piston n, the valve 19' closes, preventingescape of the air through the inlets q, and the air in the cylinder istherefore forced through the holes s in the head m into thecylinder-chamber u, the valve r openii g for thatpurpose, and by thepressure of the air. This operation eompresses ,the air in thecylinder-chamber u, and as the shaft next turns to drive thedrilLforward the valve r oloses, and as the drill-point strikes 'thestone, the rebound of the drill carries its head g against the body ofconfined and compressed air in the cylinder I), the reaction being spentupon the air, and not upon the nacline. i

Although I have shown but one 'drill-shank or holder, it will be obviousthat the machine may be made with a series of drills, to besimultanously operated to act over or across the face of a block ofstone, the drill-shanks extending from one or from several heads, and

'there being one or more air-eushioning cylin-

